1. Field of the Invention
The present invention relates to a silencer device for silencing of a flowing gas, comprising a valve which is arranged in a valve housing through which the gas is flowing.
2. Description of the Related Art
Especially in the car industry, new ways of silencing sound in, for example, exhaust systems are investigated. One method is to deliberately introduce a disturbance in the flowing gas, which causes a change in the characteristics of the sound in a positive way. A valve is arranged in the flowing gas to increase the back pressure in the exhaust system and it is controlled automatically by the pressure of the gas.
Since the flow of the exhaust gases change characteristics at a certain exhaust gas pressure, depending on motor type, it is desirable that the valve opens at different velocities at different exhaust gas pressures. At a certain pressure it is desirable that, from a sound silencing point of view, to almost momentary open the valve in full. A choke at a high pressure and large flow rates implies large losses of effect for the motor, which of course is not desirable.
Previously known valves open at a constant or inverse exponential velocity, which means that the valve opens too quickly in the beginning, whereby too little silencing occur with subsequent effect losses.
An attempt to solve this problem is shown and described in the Swedish patent application 9704221-2. Therein, a partial flow of the exhaust gases is lead to valve actuating means, which controls the opening of a valve, which is arranged in the exhaust gas flow through a silencer. The valve actuating means comprises two membranes and two different springs and a piston rod. At lower pressures the piston rod is drawn, against the biasing force of the large spring, which piston rod is connected to the valve, into the valve actuating means so that the valve is opened. When the pressure passes a predetermined valve a passage is opened, against the biasing force of the small spring between a first and a third space so that both of the membranes are influenced at the same time, whereby the piston rod is drawn into the valve actuating means quicker and the valve opens quicker.
This solution is complicated and not reliable. In order to function a most accurate manufacturing is needed with components having very small tolerances. This makes the manufacturing and also the maintenance expensive. Another essential problem with this solution is that it is impossible to design the actuating means so that it will open quickly enough after that the predetermined pressure has been achieved.
The object of the present invention is to provide a silencer device which has a simple design, is inexpensive to manufacture, reliable in use and which has actuating means, which opens the valve nearly momentary when a predetermined pressure is achieved.
These objects are met according to the invention by a silencer device according to the preamble, which is characterised in that the silencer device also comprises a separate pressure regulator, which is provided outside of the valve housing, to which pressure regulator a conduct from the valve housing is leading, which leads a portion of the flowing gas to the pressure regulator, whereby, the pressure force of the gas is convertible in the pressure regulator to a displacement motion for actuating a separate mechanical actuating means, whereby the valve (1) is openable in at least two different predetermined opening velocities, which opening velocities depend of the pressure of the gas.
Further, the actuating means gives an increased ratio after that a predetermined gas pressure has been achieved, whereby the opening velocity increases.
According to a first embodiment of the actuating means, this shows a number of hinged, rod like means.
Preferably, the rod like means move along a groove, which comprises at least two differently angled guide surfaces, each guide surface corresponds a certain opening velocity.
According to a second embodiment of the actuating means, the valve is actuatable by the actuating means by a first length of a momentum arm from an extended rotational axis of the valve whereby after that a predetermined gas pressure is achieved the valve is actuatable by the second, shorter, momentum arm from the rotational axis of the valve.
According to a third embodiment of the actuating means this shows at least two differently sized gear wheels fixedly attached to an extended rotational axle of the valve for successive co-operation with a gear rack each, which are actuatable by the pressure regulator.
The valve may, for example, be rotatably arranged around a rotational axis in the valve housing or be slided into the valve housing as a guillotine. Of course, also many other types of valves may be used.
There is a lot of advantages with the silencer device according to the invention. For example the device is small and light weighted, especially compared to conventional silencers. Another advantage is that you easily may change the ratio, i.e. the opening velocity of the valve, so that the device easily may be adapted to different motors. Additionally, it is easily to provide more ratio steps, if desired.
The silencer device according to the invention may be used in many different applications, such as exhaust systems and air intake systems for motors or other systems with flowing gas that is desirable to silence.